Let a $11$x$11$- square , that have $121$ mini-squares, and the numbers from $1$ to $121$.
Show that they can't be arranged such that two consecutive numbers stay in two mini squares that have a common edge and the numbers $1^2$, $2^2$,...,$11^2$ stay on the same column.
I think that on the line that contains $10^2$ are numbers between $90$ and $110$.
Also on the line that contains $9^2$ are numbers between $71$ and $91$ and so on.
I don't know how it can help me.


So the numbers $1^2$ through to $11^2$ fill one column. This divides the square into two parts. There are ten differences between consecutive squares, and these differences are all odd. There are an even number of distinct integers strictly between two consecutive squares.
Now at each square other than $1$ and $121$ the chain of successive digits must cross the line of squares eg $3\to 4\to 5$ and $8\to 9 \to 10$ (can't go vertically in the line of squares). Say we go left from $1$, then on the left we accumulate the differences $2, 6, 10, 14, 18$ which total $50$ and this is not divisible by $11$ - and the differences on the right are $4+8+12+16+20=60$ and this isn't divisible by $11$ either.